The rodent subfamily Sigmodontinae includes New World rats and mice, with at least 376 species. Many authorities include the Neotominae and Tylomyinae as part of a larger definition of Sigmodontinae. When those genera are included, the species count numbers at least 508. Their distribution includes much of the New World, but the genera are predominantly South American, such as brucies. They invaded South America from Central America as part of the Great American Interchange near the end of the Miocene, about 5 million years ago.[1] Sigmodontines proceeded to diversify explosively in the formerly isolated continent. They inhabit many of the same ecological niches that the Murinae occupy in the Old World.

Temporal range: Early Pliocene - recent
Sigmodon hispidus1.jpg
Hispid cotton rat (Sigmodon hispidus)
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Family: Cricetidae
Subfamily: Sigmodontinae
Wagner, 1843

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The "Thomasomyini" from the Atlantic Forest of Brazil are generally thought to be not especially related to the "real" Thomasomyini from the northern Andes and the Amazon rainforest. The genera Wiedomys and Sigmodon are generally placed in their own tribe, and the "phyllotines" Irenomys, Punomys, Euneomys, and Reithrodon are considered incertae sedis.

The name "Sigmodontinae" is based on the name of the type genus, Sigmodon. This name in turn derives from the Greek roots for "S-tooth" (sigm- for "S" and odont- for "tooth", as in orthodontist) for the characteristic of the molars having an S-shape when viewed from above.


The Sigmodontinae are divided into a number of tribes and genera:

Incertae sedis

See alsoEdit


  1. ^ Marshall, L. G.; Butler, R. F.; Drake, R. E.; Curtis, G. H.; Tedford, R. H. (1979-04-20). "Calibration of the Great American Interchange". Science. AAAS. 204 (4390): 272–279. Bibcode:1979Sci...204..272M. doi:10.1126/science.204.4390.272. PMID 17800342. S2CID 8625188. Retrieved 2008-04-15.
  2. ^ Pine, Ronald H.; Timm, R.M.; Wecksler, M. (June 2012). "A newly recognized clade of trans-Andean Oryzomyini (Rodentia: Cricetidae), with description of a new genus". Journal of Mammalogy. 93 (3): 851–870. doi:10.1644/11-MAMM-A-296.1.
  3. ^ Timm, Robert M.; Pine, R.H.; Hanson, J.D. (April 2018). "A new species of Tanyuromys Pine, Timm, and Weksler, 2012 (Cricetidae: Oryzomyini), with comments on relationships within the Orizomyini". Journal of Mammalogy. 99 (3): 608–623. doi:10.1093/jmammal/gyy042.

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